WP COmment url block

jQuery('textarea[name="comment"]').keyup(function() {
   if(isUrl(jQuery(this).val())){
      jQuery('input[type="submit"]').attr('disabled', true);
   }else{
    jQuery('input[type="submit"]').removeAttr('disabled');
   }
  });
  function isUrl(s) {
   var regexp = /(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?/
   return regexp.test(s);
  }